Abrasive articles and methods for forming same

ABSTRACT

An abrasive article including a bonded abrasive having a body of a diameter of at least 260 mm and a volume of at least 20 cubic centimeters, the body also having a bond material including an inorganic material, abrasive particles having an abrasive particle size of at least 40 microns contained in the bond material, and a certain Homogeneity Factor.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Patent Application No. 62/692,309, filed Jun. 29, 2018,entitled “ABRASIVE ARTICLES AND METHODS FOR FORMING SAME,” by SrikanthRAPAKA et al., which is assigned to the current assignee hereof andincorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION Field of the Disclosure

The present invention relates in general to abrasive articles, and inparticular, to bonded abrasive articles having a particular homogeneity.

Description of the Related Art

Abrasive articles used in machining applications typically includebonded abrasive articles and coated abrasive articles. A bonded abrasivearticle generally has a bond matrix containing abrasive particles.Bonded abrasive articles can be mounted onto a suitable machiningapparatus and used in various applications, such as shaping, grinding,polishing, and cutting. The industry continues to demand improvedabrasive tools to meet needs of gear grinding.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be better understood, and its numerousfeatures and advantages made apparent to those skilled in the art byreferencing the accompanying drawings.

FIG. 1 includes a flow chart including a process for forming an abrasivearticle according to an embodiment.

FIG. 2 includes a perspective-view illustration of an abrasive articleaccording to an embodiment.

FIG. 3 includes an ultrasound image of an abrasive article according toan embodiment.

FIG. 4 includes an ultrasound image of a conventional abrasive article.

FIG. 5 includes a normalized probability plot for Samples S1 and C1 toevaluate the Homogeneity Factor.

FIG. 6A includes a plot illustrating cylindricity vs. CMR′ of Samples S2and C2.

FIG. 6B includes a plot illustrating average straightness vs. CMR′ ofSamples S2 and C2.

DETAILED DESCRIPTION

The following is generally directed to bonded abrasive articles suitablefor use in material removal operations. The bonded abrasive articles canbe used in various applications, including for example, surfacegrinding, precision grinding operations (e.g., gear grindingoperations), and the like. In one particular aspect, the abrasivearticle may include a bonded abrasive of a certain dimension andstructure that has improved performance in foundry applications.

Reference herein to bonded abrasive articles includes reference to athree dimensional volume of an abrasive material having abrasiveparticles contained within a volume of a bond material. Bonded abrasivearticles can be distinct from coated abrasive articles that may utilizea single layer of abrasive particles contained in a layer of bond oradhesive material. Moreover, the bonded abrasive articles of embodimentsherein may include some porosity within the three-dimensional volume ofa bond material.

FIG. 1 includes a flowchart for forming an abrasive article inaccordance with an embodiment. As illustrated the process for formingthe abrasive article can begin at step 101 by forming a mixture. Themixture can be a slurry including a plurality of componentshomogeneously mixed in therein. In accordance with an embodiment, theprocess of forming the mixture can include providing a carrier material.A carrier material may be a liquid suitable for containing solidcomponents therein. For example, in one particular embodiment, thecarrier can include water, more particularly, may consist essentially ofwater such as deionized water.

The process of forming the mixture may further include adding a bondprecursor material to the carrier. A bond precursor material may be amaterial that becomes the bond material of the final-formed abrasivearticle. In accordance with an embodiment, the bond precursor materialcan include a powder material configured to form the bond material ofthe final-formed abrasive article. In one embodiment, the bond precursormaterial can include an inorganic material, such as, but not limited to,metals, metal alloys, ceramics, vitreous materials or frit materials, orany combination thereof. The bond precursor material may includeinorganic material in an amorphous phase, polycrystalline phase,monocrystalline phase, or any combination thereof.

In accordance with one embodiment, the bond precursor material may beadded in a particular content. For example, mixture may include at least1 wt % of the bond precursor material for a total weight of the mixture,such as at least 2 wt % or at least 3 wt % or at least 4 wt % or atleast 5 wt % or at least 6 wt % or at least 7 wt % or at least 8 wt % orat least 9 wt % or at least 10 wt % or at least 12 wt % or at least 14wt % or at least 16 wt % or at least 18 wt % or at least 20 wt % or atleast 22 wt % or at least 24 wt % or at least 26 wt % or at least 28 wt% or at least 30 wt %. Still, in one non-limiting embodiment, themixture may include not greater than 30 wt % of the bond precursormaterial for a total weight of the mixture, such as not greater than 28wt % or not greater than 25 wt % or not greater than 22 wt % or notgreater than 20 wt % or not greater than 18 wt % or not greater than 15wt % or not greater than 12 wt % or not greater than 10 wt % or notgreater than 8 wt % or not greater than 5 wt % or not greater than 3 wt%. The mixture may include a content of the bond precursor material inan amount within a range including any of the minimum and maximumpercentages noted above.

In accordance with another embodiment, the process of forming mixturecan include adding a gelling agent to the mixture. The addition of thegelling agent to the mixture may be completed at various times,including for example, prior to the addition of any dry components. Thegelling agent may be a material that facilitates changing the mixtureinto a gel. A gelling agent may be used in combination with gellingprocesses, including for example, the addition of heat, to facilitatethe gelation process.

In accordance with an embodiment the gelling agent may be an organicmaterial, such as a gum. For example, the gelling agent may be selectedfrom the group consisting of agar, agarose, xanthan gum, carboxy methylcellulose, gellan gum, carrageenan gum, guar gum, tara gum, cellulosegum, locust bean gum, pectin, or any combination thereof. According toone particular embodiment, the gelling agent may be preferably a gellangum. According to another particular embodiment, the gelling agent mayinclude pectin or a combination of pectin and at least one other gellingagent noted in embodiments herein.

For certain embodiments, the mixture may include a certain content ofthe gelling agent to facilitate the formation of an improved abrasivearticle. For example the mixture may include at least 0.1 wt % of thegelling agent for a total weight of the mixture, such as at least 0.2 wt% or at least 0.5 wt % or at least 0.8 wt % or at least 1 wt % or atleast 1.5 wt % or at least 2 wt % or at least 2.5 wt % or at least 3 wt% or at least 3.5 wt % or at least 4 wt % or at least 4.5 wt % or atleast 5 wt % or at least 5.5 wt % or at least 6 wt % or at least 6.5 wt% or at least 7 wt % or at least 7.5 wt %. In one non-limiting examples,the mixture may include not greater than 10 wt % of the gelling agentfor a total weight of the mixture, such as not greater than 9 wt % ornot greater than 8 wt % or not greater than 7 wt % or not greater than 6wt % or not greater than 5 wt % or not greater than 4 wt % or notgreater than 3 wt % or not greater than 2 wt % or not greater than 1 wt%. The mixture may include a content of the gelling agent in an amountwithin a range including any of the minimum and maximum percentagesnoted above.

The mixture may further include abrasive particles configured to formthe abrasive component of the final-formed abrasive article. Theabrasive particles may be added to the mixture at various times,including for example, after the addition of the bond precursor materialto the mixture. Still, it will be appreciated, in other embodiments, theabrasive particles may be added in combination with one or more of theother components in the mixture, including for example, but not limitedto the gelling agent, the bond precursor material, or one or moreadditives. The abrasive particles may include a material such as fromthe group consisting of oxides, borides, nitrides, carbides,oxynitrides, oxycarbides, amorphous, monocrystalline, polycrystalline,superabrasive or any combination thereof. In one particular embodiment,the abrasive particles can include alumina, and may consist essentiallyof alumina.

The mixture may include a certain content of abrasive particles tofacilitate suitable manufacturing and/or improved performance of theabrasive article. For example, in one embodiment, the mixture mayinclude at least 20 wt % of the abrasive particles for a total weight ofthe mixture, such as at least 22 wt % or at least 24 wt % or at least 26wt % or at least 28 wt % or at least 30 wt % or at least 35 wt % or atleast 40 wt % or at least 45 wt % or at least 50 wt % or at least 55 wt% or at least 60 wt % or at least 65 wt % or at least 70 wt %. Inanother non-limiting embodiment, the mixture may include not greaterthan 80 wt % of the abrasive particles for a total weight of themixture, such as not greater than 75 wt % or not greater than 70 wt % ornot greater than 65 wt % or not greater than 60 wt % or not greater than55 wt % or not greater than 50 wt % or not greater than 45 wt % or notgreater than 40 wt % or not greater than 35 wt % or not greater than 30wt %, such as not greater than 25 wt %. The mixture may include acontent of the abrasive particles in an amount within a range includingany of the minimum and maximum percentages noted above.

The mixture may further include one or more additives which mayfacilitate improved manufacturing and/or performance of the abrasivearticle. Some exemplary additives may include, but not limited to,dispersants, surfactants, cationic agents, or any combination thereof.As used herein, a dispersant may prevent flocculation of the mixture byelectrostatic or steric repulsion. As used herein, a surfactant maylower the surface tension between two liquids, a solid and liquid or agas and liquid. As used herein a cationic agent may be an ionic compound(e.g., a salt) that cross-links with the gelling agent, which may be ananionic material.

The one or more additives may be added to the mixture at various times,including for example, after the addition of the solid components to themixture, including for example, the bond precursor material and theabrasive particles. Still, it will be appreciated, in other embodiments,the one or more additives may be added in combination with one or moreof the other components in the mixture, including for example, but notlimited to the gelling agent, the bond precursor material, or one ormore additives. The order the additives are added may also besignificant to facilitate suitable formation of the abrasive article.For example, in at least one embodiment, the cationic agent may be addedafter any other additives are added to the mixture.

The dispersant can include at least one of sodium polyacrylate (e.g.,Darvan 811), copolymer with pigment affinic group (e.g., BYK192),ammonium polymeta acrylate (e.g., Darvan C-N), ammonium polyacrylate(e.g., Darvan 821A), polyacrylic acid, ammonium salt in an acrylicpolymer in water (e.g., Dispex), citric acid, sodiumdodecylbenzenesulfonate, cetyltrimethyl ammonium bromide or anycombination thereof.

The mixture may include a particular content of dispersant to facilitateimproved manufacturing and/or performance of the abrasive article. Forexample, the mixture can include at least 0.1 wt % of the dispersant fora total weight of the mixture, such as at least 0.2 wt % or at least 0.5wt % or at least 0.8 wt % or at least 1 wt % or at least 1.5 wt % or atleast 2 wt % or at least 2.5 wt % or at least 3 wt % or at least 3.5 wt% or at least 4 wt % or at least 4.5 wt % or at least 5 wt %. In anothernon-limiting embodiment, the mixture may include not greater than 6 wt %of the dispersant for a total weight of the mixture, such as not greaterthan 5 wt % or not greater than 4 wt % or not greater than 3 wt % or notgreater than 2 wt % or not greater than 1 wt %. The mixture may includea content of the dispersant in an amount within a range including any ofthe minimum and maximum percentages noted above.

Suitable examples of surfactants can include inorganic materials,organic materials or a combination thereof. A suitable surfactant mayinclude a sulfate, a sarconsinate, a laurate, a stearate, lecithin, andthe like. In one particular embodiment, the surfactant can includesodium lauroyl sarcosinate, sodium laurel sulfate, sodium laurate,sodium stearate, sodium alkyl sulfate, sodium dodecyl sulfate, sorbitan,polyethylene glycol, polysorbate, glycerol monosterate, egg lecithin orany combination thereof.

The mixture may include a particular content of surfactant that mayfacilitate improved manufacturing and/or performance of the abrasivearticle. For example, the mixture can include at least 0.1 wt % of thesurfactant for a total weight of the mixture, such as at least 0.2 wt %or at least 0.5 wt % or at least 0.8 wt % or at least 1 wt % or at least1.5 wt % or at least 2 wt % or at least 2.5 wt % or at least 3 wt % orat least 3.5 wt % or at least 4 wt % or at least 4.5 wt % or at least 5wt %. In another non-limiting embodiment, the mixture may include notgreater than 6 wt % of the surfactant for a total weight of the mixture,such as not greater than 5 wt % or not greater than 4 wt % or notgreater than 3 wt % or not greater than 2 wt % or not greater than 1 wt%. The mixture may include a content of the surfactant in an amountwithin a range including any of the minimum and maximum percentagesnoted above.

Some suitable examples of cationic agents can include inorganiccompounds, particularly salts, such as sulfates, chlorides, chromates,nitrates, carbonates (e.g., bicarbonates), hydrates, and the like. Inparticular instances, the cationic agent may include a compoundincluding an alkali element, alkali earth element, transition metalelement, hydrogen, or a combination thereof. More particularly, thecationic agent may include a compound including sodium, potassium,lithium, ammonium, copper, magnesium, iron, calcium, or any combinationthereof. In one particular embodiment, the cationic agent is preferablycalcium chloride or sodium chloride. For example, the cationic agent mayconsist of calcium chloride or sodium chloride.

The cationic agent may be added to the mixture at various times,including for example, after the addition of the solid components (e.g.,abrasive particles, one or more fillers, bond precursor mixture) to themixture. In one particular embodiment, the cationic agent may be thelast component added to the slurry prior to gelation. Still, it will beappreciated, in other embodiments, the cationic agent may be added incombination with one or more of the other components in the mixture,including for example, but not limited to the gelling agent, the bondprecursor material, abrasive particles or one or more additives.

The mixture may include a particular content of cationic agent that mayfacilitate improved manufacturing and/or performance of the abrasivearticle. For example, the mixture can include at least 0.1 wt % of thecationic agent for a total weight of the mixture, such as at least 0.2wt % or at least 0.5 wt % or at least 0.8 wt % or at least 1 wt % or atleast 1.5 wt % or at least 2 wt % or at least 2.5 wt % or at least 3 wt% or at least 3.5 wt % or at least 4 wt % or at least 4.5 wt % or atleast 5 wt %. In another non-limiting embodiment, the mixture mayinclude not greater than 6 wt % of the cationic agent for a total weightof the mixture, such as not greater than 5 wt % or not greater than 4 wt% or not greater than 3 wt % or not greater than 2 wt % or not greaterthan 1 wt %. The mixture may include a content of the cationic agent inan amount within a range including any of the minimum and maximumpercentages noted above.

The method of forming mixture may include continuous mixing while theone or more components are added. In particular, mixing may continuethroughout the process of adding the components. In certain instances,the components may be added in a particular order, for example thegelling agent may be added first, followed by the addition of the bondprecursor material and abrasive particles. One or more of the additivessuch as the dispersant, surfactant and cationic age may be added beforeor after the addition of the bond precursor material and/or abrasiveparticles. In a particular embodiment, the cationic agent can be addedlast of all the components. In another embodiment, a mixer may be usedto aid mixing, such as a shear mixer, a ball mill, or any combinationthereof. In an aspect, a shear mixer can be a high-shear mixer, or alow-shear mixer. In a particular aspect, to aid mixing, a shear rate maybe at least 500 S⁻¹, at least 700 S⁻¹, at least 800 S⁻¹, or at least 900S⁻¹. In another particular aspect, a shear rate may be at most 1200 S⁻¹,at most 1100 S⁻¹, or at most 1000 S⁻¹. It is to be understood, the shearrate can be within a range including any of the minimum and maximumvalues noted herein. For example, a suitable shear rate can be from 500S⁻¹ to 1200 S⁻¹.

In at least one embodiment, the method of making the abrasive articleincludes changing the mixture to a gel. The gelling of the mixture canbe facilitated by the addition of one or more of the components,including for example, the gelling agent and/or one or more additives.In accordance with one particular embodiment, the process of formingmixture into a gel can include forming a mixture first including the geland the carrier, such as water. After forming the mixture including thegel and water, the process may continue by adding at least one of a bondprecursor material, abrasive particles, and one or more additives, orany combination thereof. After adding the bond precursor material,abrasive particles, and/or one or more additives to the mixture, theprocess can continue by adding the cationic agent to the mixture. Inparticular instances, the cationic agent may be added in the final stepof forming the mixture prior to forming the mixture into a gel.

The process of forming the gel can include hydrating the gel. In aparticular embodiment, the process of forming the gel can be a processof hydrating the gel. In particular, the process of forming the gel caninclude heating the mixture to a gelling temperature. More particularly,the mixture can be mixed while heating the mixture to the gellingtemperature. In at least one embodiment, the gelling temperature can beat least 50° C., such as at least 60° C. or at least 70° C. or at least80° C. or at least 90° C. or at least 100° C. Still, in one non-limitingembodiment, the gelling temperature may be not greater than 100° C.,such as not greater than 90° C. or not greater than 80° C. or notgreater than 70° C. It will be appreciated that the gelling temperaturecan be within a range including any of the minimum and maximumtemperatures noted above.

After forming the gel, which may also be referred to herein as a foamedgel, the process can continue by forming a green body from the gel. Inaccordance with an embodiment, the process of forming the green body caninclude at least one process from the group of pressing, molding,casting, drying, freezing, cooling or any combination thereof. In oneparticular embodiment, the process of forming the green body can includecasting. Casting can be completed by pouring the gel into a productiontool or cast of a suitable shape and size. During the process of formingthe green body, some of the gel may still be forming. That is, gelationneed not necessarily be completed during the forming of the green body.Still, in certain instances it may be desirable that the mixture isentirely gelled prior to the process of forming the green body. As usedherein, reference to a gel includes a solid self-supporting structurethat includes water contained in an integrated network defined by thesolid particles in the gel. The gel may have a particular yield stress,such that it is self-supportive. For example, the gel can have a yieldstress of at least 30 Pa, such as at least 60 Pa or at least 130 Pa.

In particular implementations, the process of forming the green body caninclude de-airing during the forming of the green body. For example,de-airing may be conducted during molding to remove bubbles.

After the green body has been formed, further processes may be conductedon the green body to change or convert the green body into a bondedabrasive body. After completing step 101, the process may continue atstep 103 by forming a bonded abrasive body having a certain HomogeneityFactor. For example, one or more processes for converting the green bodyinto the final-formed bonded abrasive body can include drying,sintering, cooling, pressing, vitrifying, or any combination thereof. Inone particular embodiment, the process can include casting, cooling,drying and firing. In the context of a vitrified bond material, thefiring conditions can be suitable for forming a vitreous bond material.For example, the firing temperature can be at least 800° C. or at least900° C. or at least 1000° C. or at least 1100° C. or at least 1200° C.Still, in one embodiment, the firing temperature can be not greater than1400° C. or not greater than 1300° C. or not greater than 1200° C. ornot greater than 1100° C. or not greater than 1000° C. or not greaterthan 900° C.

The final-formed abrasive article may be a bonded abrasive body definingan interconnected network of bond material that contains abrasiveparticles in the three-dimensional volume (i.e., matrix) of the bondmaterial. Furthermore, the bonded abrasive body may have an amount ofporosity distributed throughout the body and defining a phase that isdistinct from the phases of the bond material and abrasive particles.

Bonded abrasive bodies formed by the processes of the embodiments hereinmay have particular features. For example, the bonded abrasive bodiesmay have relatively larger dimensions compared to most conventionalbonded abrasive bodies and may further have relatively larger abrasivegrit contained therein, which may be particularly suited for use inlarge-scale cutting and grinding operations, such as the foundryindustry.

FIG. 2 includes a perspective view image of a bonded abrasive body inaccordance with an embodiment. The abrasive article 200 can include abonded abrasive body 201. The bonded abrasive body 201 can include anarbor hole 202 configured to engage with a spindle of a grinding machinefor rotation of the abrasive article 200 relative to a workpiece. Asfurther illustrated in FIG. 2, the bonded abrasive body includes anaxial axis 203 defining an axial direction and a lateral axis 204defining an axis in a radial direction. The axial axis 203 extends inthe vertical direction as defined by a thickness (t) of the bondedabrasive body 201. The lateral axis 204 extends in a radial directiondefining the radius or diameter (D) of the bonded abrasive body 201.

According to one embodiment, the bonded abrasive body may have adiameter (D) of at least 260 mm, such as a diameter of at least 270 mmor at least 280 mm or at least 290 mm or at least 300 mm or at least 325mm or at least 350 mm or at least 375 mm or at least 400 mm or at least425 mm or at least 450 mm or at least 475 mm or at least 500 mm or atleast 525 mm or at least 550 mm or at least 575 mm. Still, in onenon-limiting embodiment, the bonded abrasive body may have a diameter(D) of not greater than 800 mm or not greater than 700 mm or not greaterthan 600 mm or not greater than 575 mm or not greater than 550 mm or notgreater than 525 mm or not greater than 500 mm or not greater than 475mm or not greater than 450 mm or not greater than 425 mm or not greaterthan 400 mm or not greater than 375 mm or not greater than 350 mm or notgreater than 325 mm or not greater than 300 mm or not greater than 290mm or not greater than 280 mm. It will be appreciated that the diameter(D) can be within a range including any of the minimum and maximumvalues noted above. Reference herein to a diameter may be an averagediameter of the bonded abrasive body, which is averaged from multiplemeasurements.

In another embodiment, the bonded abrasive body 201 may have aparticular volume depending upon the application. For example, thevolume of the bonded abrasive body 201 can be at least 1 cm³. In otherinstances, the volume of the bonded abrasive body 201 can be at least 10cm³ or at least 20 cm³ or at least 30 cm³ or at least 50 cm³ or at least75 cm³ or at least 100 cm³. Still, in another non-limiting embodiment,the body may have a volume of not greater than 1000 cm³ or not greaterthan 900 cm³ or not greater than 800 cm³ or not greater than 700 cm³ ornot greater than 600 cm³ or not greater than 500 cm³. It will beappreciated that the volume of the bonded abrasive body can be within arange including any of the minimum and maximum values noted above, suchas a volume of at least 10 cm³ to not greater than 1000 cm³.

In still another embodiment, the bonded abrasive body 201 may have aparticular thickness (t) configured for use in certain applications. Forexample, the bonded abrasive body 201 can have a thickness the bodycomprises a thickness of at least 2 mm, such as at least 3 mm or atleast 4 mm or at least 5 mm or at least 10 mm or at least 15 mm or atleast 20 mm or at least 30 mm or at least 50 mm or at least 100 mm or atleast 200 mm or at least 300 mm. Still, in another embodiment, thethickness (t) of the bonded abrasive body 201 can be not greater than500 mm, such as not greater than 400 mm or at least 300 mm or notgreater than 200 mm or not greater than 100 mm or not greater than 80 mmor not greater than 60 mm or not greater than 40 mm or not greater than20 mm or not greater than 10 mm. It will be appreciated that thethickness (t) of the bonded abrasive body 201 can be within a rangeincluding any of the minimum and maximum values noted above, such as avolume of at least 2 mm to not greater than 400 mm. Reference herein toa thickness may be an average thickness of the bonded abrasive body,which is averaged from multiple measurements.

The bonded abrasive body 201 may have a particular aspect ratio (D:t) ofat least 5:1, such as at least 10:1 or at least 20:1 or at least 40:1 orat least 50:1 or at least 100:1 or at least 150:1 or at least 300:1 orat least 500:1 or at least 800:1 or at least 1000:1. Still, in anothernon-limiting embodiment, the aspect ratio (D:t) may be not greater than100,000:1 or not greater than 10,000:1 or not greater than 1000:1 or notgreater than 500:1. It will be appreciated that the aspect ratio can bewithin a range including any of the minimum to maximum ratios notedabove.

The bonded abrasive body 201 may include abrasive particles having anaverage particle size (D50) of at least 40 microns. The bonded abrasivebodies herein may utilize relatively large size abrasive particles,which have historically proven difficult to homogeneously distributethroughout the mixture and resulting bonded abrasive body. Notably, dueto their relatively larger sizes, such abrasive particles have atendency to segregate and agglomerate in the gel and mixture, resultingin abrasive products with in-homogeneities and density variations. Inone particular embodiment, the abrasive particles can have an averageparticle size (D50) of at least 50 microns or at least 55 microns or atleast 60 microns or at least 65 microns or at least 70 microns or atleast 75 microns or at least 80 microns or at least 85 microns or atleast 90 microns or at least 95 microns or at least 100 microns or atleast 105 microns or at least 110 microns or at least 115 microns or atleast 120 microns or at least 130 microns or at least 150 microns or atleast 175 microns or at least 200 microns or at least 250 microns or atleast 300 microns or at least 350 microns or at least 400 microns or atleast 450 microns or at least 500 microns or at least 600 microns or atleast 700 microns or at least 800 microns. Still, in one non-limitingembodiment, the abrasive particles may have an average particle size(D50) of not greater than 5000 microns or not greater than 4000 micronsor not greater than 3000 microns or not greater than 2000 microns or notgreater than 1000 microns or not greater than 900 microns or not greaterthan 800 microns or not greater than 700 microns or not greater than 600microns or not greater than 500 microns or not greater than 400 micronsor not greater than 300 microns or not greater than 200 microns or notgreater than 150 microns or not greater than 130 microns. The abrasiveparticles may have an average particle size (D50) within a rangeincluding any of the minimum and maximum values noted above, includingfor example, but not limited to within a range of at least 50 microns tonot greater than 5000 microns or within a range of at least 100 microsto not greater than 2000 microns or within a range of at least 50microns to not greater than 800 microns or even within a range of atleast 50 microns to not greater than 400 microns.

The abrasive particles may have various compositions, shapes, sizes, andother features. For example, the abrasive particles may include anabrasive particle type such as from the group of claimed unagglomeratedparticles, agglomerated particles, shaped abrasive particles, shapedabrasive composites, constant thickness abrasive particles (CTAP),randomly shaped abrasive particles, or any combination thereof. Inanother embodiment, the abrasive particles may include a material suchas from the group of oxides, borides, nitrides, carbides, oxynitrides,oxycarbides, amorphous, monocrystalline, polycrystalline, superabrasiveor any combination thereof.

In accordance with one embodiment, the bonded abrasive body 201 may havea particular structure that may facilitate improved performance. Forexample, the bonded abrasive body 201 may include a content of abrasiveparticles of at least 20 vol % for a total volume of the bonded abrasivebody 201, such as at least 25 vol % or at least 30 vol % or at least 35vol % or at least 40 vol % or at least 45 vol % or at least 50 vol % orat least 55 vol %. Still, in one non-limiting embodiment, the bondedabrasive body 201 may include a content of abrasive particles of notgreater than 65 vol % for a total volume of the bonded abrasive body201, such as not greater than 60 vol % or not greater than 55 vol % ornot greater than 50 vol % or not greater than 45 vol % or not greaterthan 40 vol % or not greater than 35 vol % or not greater than 30 vol %.The content of abrasive particles in the bonded abrasive body 201 can bewithin a range including any of the minimum and maximum percentagesnoted above.

In one particular aspect, the bonded abrasive body 201 can include abond material including an inorganic material. Some suitable examples ofan inorganic material can include a metal, metal alloy, ceramic,vitreous phase, or any combination thereof. Furthermore, the bondmaterial may include at least one of a vitreous phase, amorphous phase,a polycrystalline phase, a monocrystalline phase, or any combinationthereof. In certain instances, the bond material can consist essentiallyof a polycrystalline phase, a vitreous phase, or a monocrystallinephase.

For at least one embodiment, the bond material may include an oxide,such as a vitreous oxide-containing material. Some suitable examples ofoxides can include silicon dioxide, boron oxide, aluminum oxide, alkalioxide (M₂O), alkaline earth oxide (MO) transition metal oxide, rareearth metal oxide, or any combination thereof. In particular instances,the bond material may be a soda-lime vitreous material, borosilicatematerial, or aluminosilicate material.

The bonded abrasive body 201 may include a particular content of bondmaterial that may facilitate improved performance. For example, thebonded abrasive body 201 may include a content of bond material of atleast 2 vol % for a total volume of the bonded abrasive body 201, suchas at least 3 vol % or at least 4 vol % or at least 5 vol % or at least6 vol % or at least 8 vol % or at least 10 vol % or at least 12 vol % orat least 14 vol % or at least 16 vol % or at least 18 vol % or at least20 vol % or at least 25 vol % or at least 30 vol % or at least 35 vol %or at least 40 vol %. Still, in one non-limiting embodiment, the bondedabrasive body 201 can include a content of bond material of not greaterthan 65 vol % for a total volume of the bonded abrasive body 201 or notgreater than 60 vol % or not greater than 55 vol % or not greater than50 vol % or not greater than 45 vol % or not greater than 40 vol % ornot greater than 35 vol % or not greater than 30 vol % or not greaterthan 25 vol % or not greater than 22 vol % or not greater than 20 vol %or not greater than 18 vol % or not greater than 16 vol % or not greaterthan 14 vol % or not greater than 12 vol % or not greater than 10 vol %or not greater than 8 vol % or not greater than 6 vol %. It will beappreciated that the content of bond material can be within a rangeincluding any of the minimum and maximum values noted above, includingfor example, a content of bond material within a range of at least 1 vol% and not greater than 15 vol % for a total volume of the body.

The bonded abrasive body 201 may include a particular structure suchthat it has a controlled content of the bond material relative to thecontent of abrasive particles. For example, in one instance, the bodycan have an ABR Factor (Cb/Cap) within a range of at least 0.5 to notgreater than 10, wherein Cb represents the vol % of the bond materialfor the total volume of the bonded abrasive body 201 and Cap representsthe vol % of the abrasive particles for the total volume of the bondedabrasive body 201. In particular instances, the bonded abrasive body 201may have an ABR Factor (Cb/Cap) of at least 0.55, such as at least 0.6or at least 0.65 or at least 0.7 or at least 0.75 or at least 0.8 or atleast 0.85 or at least 0.9 or at least 0.95 or at least 1 or at least1.05 or at least 1.1 or at least 1.15 or at least 1.2 or at least 1.25or at least 1.3 or at least 1.35 or at least 1.4 or at least 1.45 or atleast 1.5 or at least 1.55 or at least 1.6 or at least 1.65 or at least1.7 or at least 1.75 or at least 1.8 or at least 1.85 or at least 1.9 orat least 1.95 or at least 2 or at least 2.2 or at least 2.5 or at least2.8 or at least 3 or at least 3.5 or at least 4 or at least 4.5 or atleast 5 or at least 5.5 or at least 6 or at least 7 or at least 8 or atleast 9. Still, in another non-limiting embodiment, the bonded abrasivebody 201 can have an ABR Factor (Cb/Cap) of not greater than 9, such asnot greater than 8.5 or not greater than 8 or not greater than 7.5 ornot greater than 7 or not greater than 6.5 or not greater than 6 or notgreater than 5.5 or not greater than 5 or not greater than 4.5 or notgreater than 4 or not greater than 3.5 or not greater than 3 or notgreater than 2.5 or not greater than 2 or not greater than 1.5 or notgreater than 1 or not greater than 0.9. It will be appreciated that theABR Factor (Cb/Cap) can be within a range including any of the minimumand maximum values noted above.

In another embodiment, the bond abrasive body 201 may have a particulartype and content of porosity that may facilitate improved performance ofthe abrasive article. For example, the bonded abrasive body 201 can havean average pore size (D50) of at least 10 microns, such as at least 20microns or at least 30 microns or at least 40 microns or at least 50microns or at least 60 microns or at least 70 microns or at least 80microns or at least 90 microns or at least 100 microns or at least 200microns or at least 300 microns or at least 400 microns or at least 500microns or at least 600 microns or at least 700 microns or at least 800microns or at least 900 microns. Still, in one non-limiting embodiment,the average pore size (D50) of the porosity of the bonded abrasive body201 can be not greater than 1000 microns or not greater than 900 micronsor not greater than 800 microns or not greater than 700 microns or notgreater than 600 microns or not greater than 500 microns or not greaterthan 400 microns or not greater than 300 microns or not greater than 200microns or not greater than 100 microns or not greater than 80 micronsor not greater than 60 microns or not greater than 40 microns or notgreater than 20 microns or not greater than 10 microns. It will beappreciated that the average pore size can be within a range includingany of the minimum and maximum values noted above.

The bonded abrasive body 201 may have a particular content of porositythat may facilitate improved performance. For example, the bondedabrasive body 201 may include at least 20 vol % porosity for a totalvolume of the bonded abrasive body 201, such as at least 25 vol % or atleast 30 vol % or at least 35 vol % or at least 40 vol % or at least 45vol % or at least 50 vol % or at least 55 vol % or at least 60 vol % orat least 65 vol % or at least 70 vol % or at least 75 vol % or at least80 vol %. Still, in one non-limiting embodiment, the bonded abrasivebody 201 can include not greater than 95 vol % porosity for a totalvolume of the bonded abrasive body 201, such as not greater than 90 vol% or not greater than 85 vol % or not greater than 80 vol % or notgreater than 75 vol % or not greater than 70 vol % or not greater than65 vol % or not greater than 60 vol % or not greater than 55 vol % ornot greater than 50 vol % or not greater than 45 vol % or not greaterthan 40 vol % or not greater than 35 vol % or not greater than 30 vol %.It will be appreciated that the content of porosity in the bondedabrasive body 201 can be within a range including any of the minimum andmaximum percentages noted above.

The porosity of the bonded abrasive body 201 may include open porosity,closed porosity, or a combination thereof. Open porosity can be definedas interconnected channels extending through the bonded abrasive body201. Closed porosity can define discrete and isolated voids contained inthe bond material. In accordance with an embodiment,

In accordance with an embodiment, the bonded abrasive body 201 mayinclude a particular content of open porosity that may facilitateimproved performance. For example, the bonded abrasive body 201 mayinclude at least 15 vol % open porosity for a total volume of theporosity, such as at least 20 vol % or at least 30 vol % or at least 40vol % or at least 50 vol % or at least 60 vol % or at least 70 vol % orat least 80 vol % or at least 90 vol %. Still, in one non-limitingembodiment, the bonded abrasive body 201 can include not greater than 95vol % open porosity for a total volume of the porosity in the bondedabrasive body 201, such as not greater than 90 vol % or not greater than80 vol % or not greater than 70 vol % or not greater than 60 vol % ornot greater than 50 vol % or not greater than 40 vol % or not greaterthan 30 vol % or not greater than 20 vol %. In at least one embodiment,all of the porosity in the bonded abrasive body 201 can be openporosity. It will be appreciated that the content of open porosity canbe within a range including any of the minimum and maximum percentagesnoted above

In accordance with an embodiment, the bonded abrasive body 201 mayinclude a particular content of closed porosity that may facilitateimproved performance. For example, the bonded abrasive body 201 mayinclude at least 10 vol % closed porosity for a total content of theporosity in the bonded abrasive body 201, such as at least 15 vol % orat least 20 vol % or at least 30 vol % or at least 40 vol % or at least50 vol % or at least 60 vol % or at least 70 vol % or at least 80 vol %or at least 90 vol %. Still, in one non-limiting embodiment, the bondedabrasive body 201 can include not greater than 95 vol % closed porosityfor a total volume of the porosity in the bonded abrasive body 201, suchas not greater than 90 vol % or not greater than 80 vol % or not greaterthan 70 vol % or not greater than 60 vol % or not greater than 50 vol %or not greater than 40 vol % or not greater than 30 vol % or not greaterthan 20 vol %. In at least one embodiment, all of the porosity in thebonded abrasive body 201 can be closed porosity. It will be appreciatedthat the content of closed porosity can be within a range including anyof the minimum and maximum percentages noted above

The processes of the embodiments herein may facilitate formation ofbonded abrasive articles having particular grades and/or structuresutilizing relatively large abrasive particles and having a superiorhomogeneity in terms of the distribution of phases throughout the bodyin a manner that it was not previously achieved by conventionalprocessing. Notably, the bonded abrasive body 201 may have a particularhomogeneity factor of not greater than 85. For example, the HomogeneityFactor may be not greater than 84 or not greater than 82 or not greaterthan 80 or not greater than 78 or not greater than 76 or not greaterthan 74 or not greater than 72 or not greater than 70 or not greaterthan 68 or not greater than 66 or not greater than 64 or not greaterthan 62 or not greater than 60 or not greater than 58 or not greaterthan 56 or not greater than 54 or not greater than 52 or not greaterthan 50 or not greater than 48 or not greater than 46 or not greaterthan 44 or not greater than 42 or not greater than 40 or not greaterthan 38 or not greater than 36 or not greater than 34 or not greaterthan 32 or not greater than 30 or not greater than 28 or not greaterthan 26 or not greater than 24 or not greater than 22 or not greaterthan 20 or not greater than 18 or not greater than 16 or not greaterthan 14 or not greater than 12 or not greater than 10 or not greaterthan 8 or not greater than 6 or not greater than 4 or not greater than2. Still, in one non-limiting embodiment, the Homogeneity Factor may beat least 1, such as at least 2 or at least 4 or at least 6 or at least 8or at least 10 or at least 12 or at least 14 or at least 16 or at least18 or at least 20 or at least 22 or at least 24 or at least 26 or atleast 28 or at least 30 or at least 32 or at least 34 or at least 36 orat least 38 or at least 40 or at least 42 or at least 44 or at least 46or at least 48 or at least 50 or at least 52 or at least 54 or at least56 or at least 58 or at least 60 or at least 62 or at least 64 or atleast 66 or at least 68 or at least 70 or at least 72 or at least 74 orat least 76 or at least 78 or at least 80. It will be appreciated thatthe Homogeneity Factor can be within a range including any of theminimum and maximum values noted above.

The Homogeneity Factor can be evaluated by measuring the time of flightinformation through the bonded abrasive body via ultrasound systemMistras UltraPAC (UPK-T36-HS). Specifically, the bonded abrasive bodycan be submersed in water to fill all open porosity with the water. Asingle, pulse echo ultrasound sensor (Model #KS75-1) with a 1 mHzimmersion sensor and an active diameter of 19.0 mm is placed 1 inch fromthe wheel. The sensor is attached to a DC step motor that moves thesensor over the entire surface of the wheel while maintaining the 1 inchdistance. UTWin V3.62 software is used to control the movement of thestep motor. The gain is set at 10 cB, 400V pulser, LP filter of 2.0 mHz,a HP filter of 0.5 mHz, and a 100 mHz sampling rate. The data isacquired and processed by JET color map array format to create an RGBimage via the UTWin software. The scan resolution is 1.0×1.0 mm and thescan speed is 150 mm/s in the X-direction and 50 mm/s in theZ-direction.

Using the color (red-green-blue or RGB) images from the ultrasoundanalysis, the images are analyzed with image processing software, suchas Matlab. The RGB image is converted in Matlab to a LAB image using the“rgb2lab” function in Matlab, which creates a suitable image to identifyonly those areas associated with the wheel. The portions of the imagehaving a value of 100 are associated with open space (i.e., not thewheel) and removed from the image.

Next, the RGB image is converted into an index image where each pixel isassigned a color value out of 256 possible colors (i.e., values from0-255). This is completed using the “rgb2ind” function of Matlab. Thedarkest blue is associated with the lowest value or 0 and the brightestred is associated with the highest value or 255.

After the index image is created, it is compared to the LAB image toensure that only those pixels associated with the wheel are evaluated.The comparison is completed using a logical indexing operation wherepixels from the index image that are not associated with wheel area areremoved from further analysis. The result is an area-corrected indeximage.

The area-corrected index image is then used to create a normalizedprobability plot as illustrated in FIG. 5. Each box on the plotrepresents 5 sequential values between 0 and 255. For example, the firstbox (furthest left) represents the number of pixels having a valuebetween 0 and 4. From the normalized probability plot and data used togenerate the plot, statistical percentiles are evaluated. Thepercentiles include the 25^(th) percentile, 50^(th) percentile and75^(th) percentile. The Homogeneity Factor is the difference between the75^(th) percentile and the 25^(th) percentile. A body with a greaterhomogeneity of its components has less spread in the distributionbetween 0-255 and thus also has a lower difference between the 75^(th)percentile and the 25^(th) percentile.

Many different aspects and embodiments are possible. Some of thoseaspects and embodiments are described herein. After reading thisspecification, skilled artisans will appreciate that those aspects andembodiments are only illustrative and do not limit the scope of thepresent invention. Embodiments may be in accordance with any one or moreof the embodiments as listed below.

Embodiments

Embodiment 1. An abrasive article comprising:

a bonded abrasive having a body comprising a diameter of at least 260 mmand a volume of at least 20 cubic centimeters, the body furthercomprising:a bond material comprising an inorganic material;abrasive particles contained within the body, wherein the abrasiveparticles have an average particle size (D50) of at least 40 microns;anda Homogeneity Factor of not greater than 85.

Embodiment 2. The abrasive article of embodiment 1, wherein the bodycomprises an ABR Factor (Cb/Cap) within a range of at least 0.5 to notgreater than 10, wherein Cb represents the vol % of the bond materialfor the total volume of the body and Cap represents the vol % of theabrasive particles for the total volume of the body.

Embodiment 3. The abrasive article of embodiment 2, wherein the bodycomprises an ABR Factor (Cb/Cap) of at least 0.55 or at least 0.6 or atleast 0.65 or at least 0.7 or at least 0.75 or at least 0.8 or at least0.85 or at least 0.9 or at least 0.95 or at least 1 or at least 1.05 orat least 1.1 or at least 1.15 or at least 1.2 or at least 1.25 or atleast 1.3 or at least 1.35 or at least 1.4 or at least 1.45 or at least1.5 or at least 1.55 or at least 1.6 or at least 1.65 or at least 1.7 orat least 1.75 or at least 1.8 or at least 1.85 or at least 1.9 or atleast 1.95 or at least 2 or at least 2.2 or at least 2.5 or at least 2.8or at least 3 or at least 3.5 or at least 4 or at least 4.5 or at least5 or at least 5.5 or at least 6 or at least 7 or at least 8 or at least9.

Embodiment 4. The abrasive article of embodiment 2, wherein the bodycomprises an ABR Factor (Cb/Cap) of not greater than 9 or not greaterthan 8.5 or not greater than 8 or not greater than 7.5 or not greaterthan 7 or not greater than 6.5 or not greater than 6 or not greater than5.5 or not greater than 5 or not greater than 4.5 or not greater than 4or not greater than 3.5 or not greater than 3 or not greater than 2.5 ornot greater than 2 or not greater than 1.5 or not greater than 1 or notgreater than 0.9.

Embodiment 5. The abrasive article of embodiment 1, wherein the bodycomprises a Homogeneity Factor of at least 1 or at least 2 or at least 4or at least 6 or at least 8 or at least 10 or at least 12 or at least 14or at least 16 or at least 18 or at least 20 or at least 22 or at least24 or at least 26 or at least 28 or at least 30 or at least 32 or atleast 34 or at least 36 or at least 38 or at least 40 or at least 42 orat least 44 or at least 46 or at least 48 or at least 50 or at least 52or at least 54 or at least 56 or at least 58 or at least 60 or at least62 or at least 64 or at least 66 or at least 68 or at least 70 or atleast 72 or at least 74 or at least 76 or at least 78 or at least 80.

Embodiment 6. The abrasive article of embodiment 1, wherein theHomogeneity Factor is not greater than 84 or not greater than 82 or notgreater than 80 or not greater than 78 or not greater than 76 or notgreater than 74 or not greater than 72 or not greater than 70 or notgreater than 68 or not greater than 66 or not greater than 64 or notgreater than 62 or not greater than 60 or not greater than 58 or notgreater than 56 or not greater than 54 or not greater than 52 or notgreater than 50 or not greater than 48 or not greater than 46 or notgreater than 44 or not greater than 42 or not greater than 40 or notgreater than 38 or not greater than 36 or not greater than 34 or notgreater than 32 or not greater than 30 or not greater than 28 or notgreater than 26 or not greater than 24 or not greater than 22 or notgreater than 20 or not greater than 18 or not greater than 16 or notgreater than 14 or not greater than 12 or not greater than 10 or notgreater than 8 or not greater than 6 or not greater than 4 or notgreater than 2.

Embodiment 7. The abrasive article of embodiment 1, wherein the bodycomprises a diameter of at least 270 mm or at least 280 mm or at least290 mm or at least 300 mm or at least 325 mm or at least 350 mm or atleast 375 mm or at least 400 mm or at least 425 mm or at least 450 mm orat least 475 mm or at least 500 mm or at least 525 mm or at least 550 mmor at least 575 mm.

Embodiment 8. The abrasive article of embodiment 1, wherein the bodycomprises a diameter of not greater than 800 mm or not greater than 700mm or not greater than 600 mm or not greater than 575 mm or not greaterthan 550 mm or not greater than 525 mm or not greater than 500 mm or notgreater than 475 mm or not greater than 450 mm or not greater than 425mm or not greater than 400 mm or not greater than 375 mm or not greaterthan 350 mm or not greater than 325 mm or not greater than 300 mm or notgreater than 290 mm or not greater than 280 mm.

Embodiment 9. The abrasive article of embodiment 1, wherein the diameteris within a range of at least 260 mm to not greater than 600 mm.

Embodiment 10. The abrasive article of embodiment 1, wherein the bodycomprises a volume of at least 1 cm³.

Embodiment 11. The abrasive article of embodiment 1, wherein the bodycomprises a volume of not greater than 1000 cm3.

Embodiment 12. The abrasive article of embodiment 1, wherein the bodycomprises a volume of at least 1 cm3 to not greater than 1000 cm3.

Embodiment 13. The abrasive article of embodiment 1, wherein the bodycomprises a thickness of at least 2 mm.

Embodiment 14. The abrasive article of embodiment 1, wherein the bodycomprises a thickness of not greater than 500 mm

Embodiment 15. The abrasive article of embodiment 1, wherein the bodycomprises a thickness within a range of at least 2 mm and not greaterthan 500 mm.

Embodiment 16. The abrasive article of embodiment 1, wherein the bodycomprises a thickness within a range of at least 4 mm and not greaterthan 20 mm.

Embodiment 17. The abrasive article of embodiment 1, wherein theporosity comprises an average pore size (D50) within a range of at least10 microns and not greater than 1000 microns.

Embodiment 18. The abrasive article of embodiment 1, wherein the bodycomprises a porosity of at least 20 vol % for a total volume of the bodyor at least 25 vol % or at least 30 vol % or at least 35 vol % or atleast 40 vol % or at least 45 vol % or at least 50 vol % or at least 55vol % or at least 60 vol % or at least 65 vol % or at least 70 vol % orat least 75 vol % or at least 80 vol %.

Embodiment 19. The abrasive article of embodiment 1, wherein the bodycomprises a porosity of not greater than 95 vol % for a total volume ofthe body or not greater than 90 vol % or not greater than 85 vol % ornot greater than 80 vol % or not greater than 75 vol % or not greaterthan 70 vol % or not greater than 65 vol % or not greater than 60 vol %or not greater than 55 vol % or not greater than 50 vol % or not greaterthan 45 vol % or not greater than 40 vol % or not greater than 35 vol %or not greater than 30 vol %.

Embodiment 20. The abrasive article of embodiment 1, wherein the bodycomprises a porosity within a range of at least 20 vol % and not greaterthan 95 vol % for a total volume of the body.

Embodiment 21. The abrasive article of embodiment 1, wherein at least aportion of the total porosity is open porosity, wherein the openporosity defines interconnected channels extending through the body.

Embodiment 22. The abrasive article of embodiment 21, wherein the bodycomprises at least 10 vol % open porosity for a total content of theporosity in the body or at least 15 vol % or at least 20 vol % or atleast 30 vol % or at least 40 vol % or at least 50 vol % or at least 60vol % or at least 70 vol % or at least 80 vol % or at least 90 vol % orwherein essentially all of the porosity is open porosity.

Embodiment 23. The abrasive article of embodiment 21, wherein the bodycomprises not greater than 95 vol % open porosity for a total content ofthe porosity in the body or not greater than 90 vol % or not greaterthan 80 vol % or not greater than 70 vol % or not greater than 60 vol %or not greater than 50 vol % or not greater than 40 vol % or not greaterthan 30 vol % or not greater than 20 vol %.

Embodiment 24. The abrasive article of embodiment 1, wherein at least aportion of the total porosity is closed porosity, wherein the closedporosity defines discrete and isolated voids contained in the bondmaterial.

Embodiment 25. The abrasive article of embodiment 24, wherein the bodycomprises at least 10 vol % closed porosity for a total content of theporosity in the body or at least 15 vol % or at least 20 vol % or atleast 30 vol % or at least 40 vol % or at least 50 vol % or at least 60vol % or at least 70 vol % or at least 80 vol % or at least 90 vol % orwherein essentially all of the porosity is closed porosity.

Embodiment 26. The abrasive article of embodiment 24, wherein the bodycomprises not greater than 95 vol % closed porosity for a total contentof the porosity in the body or not greater than 90 vol % or not greaterthan 80 vol % or not greater than 70 vol % or not greater than 60 vol %or not greater than 50 vol % or not greater than 40 vol % or not greaterthan 30 vol % or not greater than 20 vol %.

Embodiment 27. The abrasive article of embodiment 1, wherein theabrasive particles have an average particle size (D50) of at least 45microns or at least 50 microns or at least 55 microns or at least 60microns or at least 65 microns or at least 70 microns or at least 75microns or at least 80 microns or at least 85 microns or at least 90microns or at least 95 microns or at least 100 microns or at least 105microns or at least 110 microns or at least 115 microns or at least 120microns or at least 130 microns or at least 150 microns or at least 175microns or at least 200 microns or at least 250 microns or at least 300microns or at least 350 microns or at least 400 microns or at least 450microns or at least 500 microns or at least 600 microns or at least 700microns or at least 800 microns.

Embodiment 28. The abrasive article of embodiment 1, wherein theabrasive particles have an average particle size (D50) of not greaterthan 5000 microns or not greater than 4000 microns or not greater than3000 microns or not greater than 2000 microns or not greater than 1000microns or not greater than 900 microns or not greater than 800 micronsor not greater than 700 microns or not greater than 600 microns or notgreater than 500 microns or not greater than 400 microns or not greaterthan 300 microns or not greater than 200 microns or not greater than 150microns or not greater than 130 microns.

Embodiment 29. The abrasive article of embodiment 1, wherein theabrasive particles comprise an abrasive particle type selected from thegroup consisting of unagglomerated particles, agglomerated particles,shaped abrasive particles, shaped abrasive composites, constantthickness abrasive particles (CTAP), randomly shaped abrasive particles,or any combination thereof.

Embodiment 30. The abrasive article of embodiment 1, wherein theabrasive particles comprise a material selected from the groupconsisting of oxides, borides, nitrides, carbides, oxynitrides,oxycarbides, amorphous, monocrystalline, polycrystalline, superabrasiveor any combination thereof.

Embodiment 31. The abrasive article of embodiment 1, wherein the bodycomprises a content of abrasive particles of at least 20 vol % for atotal volume of the body or at least 25 vol % or at least 30 vol % or atleast 35 vol % or at least 40 vol % or at least 45 vol % or at least 50vol % or at least 55 vol %.

Embodiment 32. The abrasive article of embodiment 1, wherein the bodycomprises a content of abrasive particles of not greater than 65 vol %for a total volume of the body or not greater than 60 vol % or notgreater than 55 vol % or not greater than 50 vol % or not greater than45 vol % or not greater than 40 vol % or not greater than 35 vol % ornot greater than 30 vol %.

Embodiment 33. The abrasive article of embodiment 1, wherein the bodycomprises a content of abrasive particles within a range of at least 20vol % and not greater than 50 vol % for a total volume of the body.

Embodiment 34. The abrasive article of embodiment 1, wherein the bodycomprises a content of bond material of at least 1 vol % for a totalvolume of the body or at least 2 vol % or at least 3 vol % or at least 4vol % or at least 5 vol % or at least 6 vol % or at least 8 vol % or atleast 10 vol % or at least 12 vol % or at least 14 vol % or at least 16vol % or at least 18 vol % or at least 20 vol % or at least 25 vol % orat least 30 vol % or at least 35 vol % or at least 40 vol %.

Embodiment 35. The abrasive article of embodiment 1, wherein the bodycomprises a content of bond material of not greater than 65 vol % for atotal volume of the body or not greater than 60 vol % or not greaterthan 55 vol % or not greater than 50 vol % or not greater than 45 vol %or not greater than 40 vol % or not greater than 35 vol % or not greaterthan 30 vol % or not greater than 25 vol % or not greater than 22 vol %or not greater than 20 vol % or not greater than 18 vol % or not greaterthan 16 vol % or not greater than 14 vol % or not greater than 12 vol %or not greater than 10 vol % or not greater than 8 vol % or not greaterthan 6 vol %.

Embodiment 36. The abrasive article of embodiment 1, wherein the bodycomprises a content of bond material within a range of at least 1 vol %and not greater than 15 vol % for a total volume of the body.

Embodiment 37. The abrasive article of embodiment 1, wherein the bondmaterial comprises an inorganic material selected from the groupconsisting of metal, metal alloy, ceramic, vitreous, or any combinationthereof.

Embodiment 38. The abrasive article of embodiment 1, wherein the bondmaterial comprises a polycrystalline phase, an amorphous phase, amonocrystalline phase, or any combination thereof.

Embodiment 39. The abrasive article of embodiment 1, wherein the bondmaterial consists essentially of a polycrystalline phase, an amorphousphase, or a monocrystalline phase.

Embodiment 40. The abrasive article of embodiment 1, wherein the bondmaterial comprises an oxide.

Embodiment 41. The abrasive article of embodiment 1, wherein the bondmaterial comprises at least one composition selected from the groupconsisting of silicon dioxide (SiO2), boron oxide (B2O3), aluminum oxide(Al2O3), alkali oxide (M2O), alkaline earth oxide (MO) transition metaloxide, rare earth metal oxide, or any combination thereof.

Embodiment 42. A method of making an abrasive article comprising:

forming a mixture comprising abrasive particles, a bond precursormaterial and a gelling agent; forming a bonded abrasive body from themixture, wherein the bonded abrasive body comprises a bond materialcomprising an inorganic material and further comprising a HomogeneityFactor of not greater than 85.

Embodiment 43. A method of making an abrasive article comprising:

forming a mixture comprising abrasive particles, a bond precursormaterial and a gelling agent;adding a cationic agent to the mixture and forming a gel;forming a green body from the gel; andforming a bonded abrasive body from the green body.

Embodiment 44. The method of embodiment 42, wherein forming a mixturefurther includes adding a cationic agent to the mixture and forming agel.

Embodiment 45. The method of any one of embodiments 43 and 44, whereinthe cationic agent comprises a cation selected from the group consistingof sodium, potassium, lithium, ammonium, copper, magnesium, iron,calcium, or any combination thereof.

Embodiment 46. The method of any one of embodiments 43 and 44, whereinthe mixture includes at least 0.1 wt % of the cationic agent for a totalweight of the mixture.

Embodiment 47. The method of any one of embodiments 43 and 44, whereinthe mixture includes not greater than 6 wt % of the cationic agent for atotal weight of the mixture.

Embodiment 48. The method of any one of embodiments 42 and 43, whereinthe gelling agent is selected from the group consisting of agar,agarose, xanthan gum, carboxy methyl cellulose, gellan gum, carrageenangum, guar gum, tara gum, cellulose gum, locust bean gum, or anycombination thereof.

Embodiment 49. The method of any one of embodiments 42 and 43, whereinthe mixture includes at least 0.1 wt % of the gelling agent for a totalweight of the mixture.

Embodiment 50. The method of any one of embodiments 42 and 43, whereinthe mixture includes not greater than 10 wt % of the gelling agent for atotal weight of the mixture.

Embodiment 51. The method of any one of embodiments 42 and 43, whereinthe abrasive particles comprise a material selected from the groupconsisting of oxides, borides, nitrides, carbides, oxynitrides,oxycarbides, amorphous, monocrystalline, polycrystalline, superabrasiveor any combination thereof.

Embodiment 52. The method of any one of embodiments 42 and 43, whereinthe mixture includes at least 20 wt % of the abrasive particles for atotal weight of the mixture.

Embodiment 53. The method of any one of embodiments 42 and 43, whereinthe mixture includes not greater than 80 wt % of the abrasive particlesfor a total weight of the mixture.

Embodiment 54. The method of any one of embodiments 42 and 43, whereinthe bond precursor material comprises an inorganic material selectedfrom the group consisting of metal, metal alloy, ceramic, vitreous, orany combination thereof.

Embodiment 55. The method of any one of embodiments 42 and 43, whereinthe mixture includes at least 1 wt % of the bond precursor material fora total weight of the mixture.

Embodiment 56. The method of any one of embodiments 42 and 43, whereinthe mixture includes not greater than 30 wt % of the bond precursormaterial for a total weight of the mixture.

Embodiment 57. The method of any one of embodiments 42 and 43, furthercomprising forming a gel by heating the mixture to a gellingtemperature.

Embodiment 58. The method of embodiment 57, wherein the mixture is mixedwhile heating the mixture to a gelling temperature.

Embodiment 59. The method of embodiment 57, wherein the gellingtemperature is at least 50° C. or at least 60° C. or at least 70° C. orat least 80° C. or at least 90° C. or at least 100° C. or at least 120°C. or at least 150° C.

Embodiment 60. The method of embodiment 57, wherein the gellingtemperature is not greater than 300° C. or not greater than 150° C. ornot greater than 200° C. or not greater than 150° C. or not greater than100° C. or not greater than 90° C.

Embodiment 61. The method of any one of embodiments 42 and 43, whereinforming the mixture further includes adding a carrier comprising water.

Embodiment 62. The method of any one of embodiments 42 and 43, whereinforming the mixture into a gel includes:

a) forming a mixture including the gel and the water;b) adding one of a bond precursor material, the abrasive particles or anadditive to the mixture after step a); andc) adding a cationic agent to the mixture after step b).

Embodiment 63. The method of any one of embodiments 42 and 43, whereinforming the mixture includes adding a dispersant to the mixture, whereinthe dispersant is selected from the group consisting of sodiumpolyacrylate, copolymer with pigment affinic group, ammonium polymetaacrylate, ammonium polyacrylate, polyacrylic acid, ammonium salt in anacrylic polymer in water, citric acid, sodium dodecylbenzenesulfonate,cetyltrimethyl ammonium bromide.

Embodiment 64. The method of any one of embodiments 43 and 44, whereinthe mixture includes at least 0.1 wt % of a dispersant for a totalweight of the mixture.

Embodiment 65. The method of any one of embodiments 43 and 44, whereinthe mixture includes not greater than 6 wt % of a dispersant for a totalweight of the mixture.

Embodiment 66. The method of any one of embodiments 42 and 43, whereinforming the mixture includes adding a surfactant to the mixture, whereinthe surfactant is selected from the group consisting of sodium lauroylsarcosinate, sodium laurel sulfate, sodium laurate, sodium stearate,sodium alkyl sulfate, sodium dodecyl sulfate, sorbitan, polyethyleneglycol, polysorbate, glycerol monosterate, egg lecithin.

Embodiment 67. The method of any one of embodiments 42 and 43, whereinthe mixture includes at least 0.1 wt % of a surfactant for a totalweight of the mixture.

Embodiment 68. The method of any one of embodiments 43 and 44, whereinthe mixture includes not greater than 6 wt % of a surfactant for a totalweight of the mixture.

Embodiment 69. The method embodiment 42, further comprising:

forming a gel from the mixture; and

forming a green body from the gel.

Embodiment 70. The method of any one of embodiments 43 and 69, whereinforming the green body includes at least one process selected from thegroup consisting of pressing, molding, casting, drying, or anycombination thereof.

Embodiment 71. The method of any one of embodiments 43 and 69, whereinthe gel includes a solid self-supporting structure that includes watercontained in an integrated network.

EXAMPLES Example 1

A representative sample (Sample S1) is made according to the followingprocess. A carrier of deionized water is obtained and approximately 3000kg of water is measured. Approximately 10,000 kg of abrasive particleshaving an average particle size (D50) of approximately 220 microns, andcommercially available as white fused alundum from Saint-GobainCorporation, is prepared. Approximately 2200 kg of bond precursormaterial, commercially available as Vitrium from Saint-GobainCorporation, is also prepared. Approximately 20 g of a surfactant,commercially available as Perlastan L30 from Schill & Seilacher GmbH, isalso prepared. Approximately 120 g of a gelling agent, commerciallyavailable as Kelcogel from CP Kelco Corporation, is prepared.Approximately 60 g of a dispersant commercially available as Darvan 821Afrom Vanderbilt Minerals is also prepared. Approximately 20 g of acationic agent commercially available as calcium chloride from FisherScientific is prepared.

The gelling agent is added to the water while stirring. During mixingthe mixture is heated at a gelling temperature of approximately 80-85°C. The bond precursor material is then added to the gel, followed by thedispersant, followed by the abrasive particles, followed by thesurfactant, and finally the cationic agent is added last. The additionof the cationic agent initiates cross-linking and the formation of thegel. Mixing is continued in a reduced pressure atmosphere ofapproximately 0.5-0.99 bar to remove larger pores from the gel.

The gel is then poured into a production tool to cast a green body fromthe gel. During casting, no additional pressure or temperature isapplied to the gel, and the gel is free cast to form the green body. Thegel dries, and the green body stabilizes. It will be understood, thatother processes may optionally apply pressure to the gel to form thegreen body.

After forming the green body from the gel, the green body is fired tocreate a vitreous bond material from the bond precursor material. Thefiring schedule includes a ramp of approximately 100° C./hr from roomtemperature to a firing temperature of approximately 910-925° C. with ahold for approximately 8 hours under a normal atmosphere. After asuitable time at the firing temperature, the fired body is cooled with aramp down of approximately 30° C./hr.

The abrasive article undergoes finishing to finalize the dimensions ofthe bonded abrasive body. The bonded abrasive body has a HomogeneityFactor of approximately 62, 13 vol % bond material that consistsessentially of a vitreous material, approximately 44 vol % abrasiveparticles, approximately 43 vol % porosity, including approximately 30vol % open porosity for the total content of porosity and approximately70 vol % closed porosity for the total content of porosity, and anaverage pore size of approximately 110 microns. Additionally, the bondedabrasive body of Sample S1 has a diameter of 127 mm, a thickness ofapproximately 25 mm, and a volume of approximately 225 cm³.

FIG. 3 includes an ultrasound image of Sample S1 used to evaluate theHomogeneity Factor.

Example 2

A conventional sample (Sample C1) is formed according to the followingprocess. Abrasive is weighed and mixed in a large mixer with dextrin asthe binder. The contents are mixed for 5 minutes. Animal glue is thenadded to the mix and mixed for 3 minutes. Mixing is stopped when theanimal glue wets the surface of the abrasive grain for the dextrin tocoat uniformly on the surface. The bond is then added to the mix and thecontents are mixed for 5 minutes till the bond uniformly coats theabrasive grain. Another round of dextrin is added to the mix to impartnecessary green strength to survive compaction step. The mix is thensieved to remove large clumps and then distributed evenly into a mold.The mold is then raked to remove air and the mix is compacted/pressed(80 tonnes of force applied) to the desired volume. The wheels are thendried for 12 hours at 80° C. and fired at 915° C. at a ramp rate of 100°C./hr and soaked for 8 hours. The wheel is then finished to accepteddimensions and analyzed using ultrasound technique.

The bonded abrasive wheel includes 13 vol % bond, 44 vol % abrasives and43 vol % porosity.

FIG. 4 includes an ultrasound image of Sample C1 used to evaluate theHomogeneity Factor. FIG. 5 includes a normalized probability plot forSamples S1 and C1 as analyzed by ultrasound for evaluation of theHomogeneity Factor. Sample S1 has a Homogeneity Factor of 62 and SampleC1 has a Homogeneity Factor of 86.

Example 3

Samples S2 and C2 were formed including the same components as thecomponents of Sample S1. All the components were mixed in the samemanner as described in Example 1. The gels for Samples S2 and C2 werepoured into a mold. Only the gel of Sample S2 was de-aired to removebubbles during molding. The green bodies were fired at the samecondition as described in Example 1.

Samples S2 and C2 were tested at the same shear rate for 3-dimensionaltolerance and taper tolerance. FIGS. 6A and 6B include plots ofcylindricity vs. CMR′ and average straightness vs. CMR′, respectively.Sample S2 demonstrated improved cylindricity and hence improved3-dimensional tolerance compared to C2 at the same testing condition.Sample S2 also had improved average straightness (also referred to astaper tolerance), as illustrated in FIG. 6B, compared to Sample C2.

Example 4

Sample S3 is formed having a diameter of at least 260 mm, thickness ofat least 2 mm, and a Homogeneity Factor not greater than 85, in the samemanner as described in Example 1. Sample S3 is expected to perform withimproved consistency when tested on grinding at least 5 to 10 workpiecesusing the same cartridge of a grinding tool and to provide improvedsurface finish on workpieces using a new cartridge for each workpiece,compared to a conventionally formed abrasive article tested under thesame condition.

The specification and illustrations of the embodiments described hereinare intended to provide a general understanding of the structure of thevarious embodiments. The specification and illustrations are notintended to serve as an exhaustive and comprehensive description of allof the elements and features of apparatus and systems that use thestructures or methods described herein. Separate embodiments may also beprovided in combination in a single embodiment, and conversely, variousfeatures that are, for brevity, described in the context of a singleembodiment, may also be provided separately or in any sub combination.Further, reference to values stated in ranges includes each and everyvalue within that range. Many other embodiments may be apparent toskilled artisans only after reading this specification. Otherembodiments may be used and derived from the disclosure, such that astructural substitution, logical substitution, or another change may bemade without departing from the scope of the disclosure. Accordingly,the disclosure is to be regarded as illustrative rather thanrestrictive. Benefits, other advantages, and solutions to problems havebeen described above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims.

The description in combination with the figures is provided to assist inunderstanding the teachings disclosed herein. The following discussionwill focus on specific implementations and embodiments of the teachings.This focus is provided to assist in describing the teachings and shouldnot be interpreted as a limitation on the scope or applicability of theteachings. However, other teachings can certainly be used in thisapplication.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a method,article, or apparatus that comprises a list of features is notnecessarily limited only to those features but may include otherfeatures not expressly listed or inherent to such method, article, orapparatus. Further, unless expressly stated to the contrary, “or” refersto an inclusive-or and not to an exclusive-or. For example, a conditionA or B is satisfied by any one of the following: A is true (or present)and B is false (or not present), A is false (or not present) and B istrue (or present), and both A and B are true (or present)

Also, the use of “a” or “an” is employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural, or vice versa, unless it is clear that it is meantotherwise. For example, when a single item is described herein, morethan one item may be used in place of a single item. Similarly, wheremore than one item is described herein, a single item may be substitutedfor that more than one item.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. The materials, methods, andexamples are illustrative only and not intended to be limiting. To theextent not described herein, many details regarding specific materialsand processing acts are conventional and may be found in reference booksand other sources within the structural arts and correspondingmanufacturing arts.

The above-disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments, which fall withinthe true scope of the present invention. Thus, to the maximum extentallowed by law, the scope of the present invention is to be determinedby the broadest permissible interpretation of the following claims andtheir equivalents and shall not be restricted or limited by theforegoing detailed description.

1. An abrasive article comprising: a bonded abrasive having a bodycomprising: a bond material comprising an inorganic material; abrasiveparticles contained within the body, wherein the abrasive particles havean average particle size (D50) of at least 40 microns; and a HomogeneityFactor of not greater than
 85. 2. The abrasive article of claim 1,wherein the body comprises a diameter of at least 260 mm and a volume ofat least 20 cm³.
 3. The abrasive article of claim 1, wherein the bodycomprises a thickness of at least 2 mm.
 4. The abrasive article of claim1, wherein the body comprises a thickness within a range of at least 4mm and not greater than 500 mm.
 5. The abrasive article of claim 1,wherein the body comprises an ABR Factor (Cb/Cap) within a range of atleast 0.5 to not greater than 10, wherein Cb represents the vol % of thebond material for the total volume of the body and Cap represents thevol % of the abrasive particles for the total volume of the body.
 6. Theabrasive article of claim 1, wherein the porosity comprises an averagepore size (D50) within a range of at least 10 microns and not greaterthan 1000 microns.
 7. The abrasive article of claim 1, wherein the bodycomprises a total porosity within a range of at least 20 vol % and notgreater than 95 vol % for a total volume of the body.
 8. The abrasivearticle of claim 7, wherein at least a portion of the total porosity isopen porosity, wherein the open porosity defines interconnected channelsextending through the body.
 9. The abrasive article of claim 7, whereinat least a portion of the total porosity is closed porosity, wherein theclosed porosity defines discrete and isolated voids contained in thebond material.
 10. The abrasive article of claim 1, wherein the abrasiveparticles have an average particle size (D50) of at least 65 microns.11. The abrasive article of claim 1, wherein the abrasive particlescomprise a material selected from the group consisting of oxides,borides, nitrides, carbides, oxynitrides, oxycarbides, amorphous,monocrystalline, polycrystalline, superabrasive or any combinationthereof.
 12. The abrasive article of claim 1, wherein the body comprisesa content of the abrasive particles of at least 20 vol % and not greaterthan 65 vol % for a total volume of the body.
 3. (canceled)
 14. Theabrasive article of claim 1, wherein the body comprises a content of thebond material within a range of at least 1 vol % and not greater than 15vol % for a total volume of the body.
 15. The abrasive article of claim1, wherein the bond material comprises an inorganic material selectedfrom the group consisting of metal, metal alloy, ceramic, vitreous, orany combination thereof.
 16. The abrasive article of claim 1, whereinthe bond material comprises a polycrystalline phase, an amorphous phase,a monocrystalline phase, or any combination thereof.
 17. The abrasivearticle of claim 1, wherein the bond material comprises an oxide. 18.The abrasive article of claim 1, wherein the bond material comprises atleast one composition selected from the group consisting of silicondioxide (SiO₂), boron oxide (B₂O₃), aluminum oxide (Al₂O₃), alkali oxide(M₂O), alkaline earth oxide (MO) transition metal oxide, rare earthmetal oxide, or any combination thereof.
 19. A method of making anabrasive article comprising: forming a mixture comprising abrasiveparticles, a bond precursor material and a gelling agent; forming abonded abrasive body from the mixture, wherein the bonded abrasive bodycomprises a bond material comprising an inorganic material and furthercomprising a Homogeneity Factor of not greater than
 85. 20. The methodof claim 19, wherein forming a mixture further includes adding acationic agent to the mixture and forming a gel, wherein the cationicagent includes a compound including sulfates, chlorides, chromates,nitrates, carbonates e.g., bicarbonates), hydrates or any combinationthereof.
 21. The abrasive article of claim 1, wherein the body comprisesa content of the bond material of at least 1 vol % and not greater than65 vol % for a total volume of the body.